Effect of Central Muscarine Receptor Blockade with DKJ-21 on the Blood Pressure and Heart Rate in Stress-Induced Hypertensive Rats

Da-Nian Zhu, Long-Mei Xue, Peng Li. Effect of central muscarine receptor blockade. with DKJ-21 on the blood pressure and heart rote in stress-induced hypertensive rats.

The experiments were performed on Wistar or Sprague-Dawley rats of both sexes divided at random into stress and control groups. The rats in the stress groups were put into cages and subjected to electric foot-shocks and noises for 9-15 days, which caused an increase in blood pressure (BP) and heart rate (HR). In hypertensive rats DKJ-21 (4mg/lml) was injected intravenously (i.v.), and 0.5-1.0h after administration the BP and HR dropped from the high level to normotensive level. In normotensive rats, however, administration of DKJ-21 had no effect on BP or HR. In separate groups of normotensive rats, pretreatment of DKJ-21 (4 mg/l ml, i.v.) blocked the pressor and tachycardiac effect induced by microinjection of physostigmine (0.4μg/0.1 /μl/site), corticosterone (40μg/0.1μl/site) or aldosterone (40 μg/0.1 μl/site) into the rostral ventrolateral medulla (rVLM). Furthermore, DKJ-21 also attenuated the enhancement of the pressor response to stimulation of the defense area in the midbrain, which was induced by microinjection of drugs (mentioned above) into the rVLM. These results indicate that i.v. DKJ-21 can selectively block the muscarinic receptors in the rVLM in stress-induced hypertensive rats, which suggests that abnormal enhancement of cholinergic mechanism in the rVLM may be related to hypertensive effects of corticoids in this area.     

Quality of life on treatment with Metoprolol in Dilated Cardiomyopathy: Results from the MDC trial

Summary Quality of life in heart failure patients is receiving increased attention as a reflection of a treatment's potential secondary benefit of general well-being and daily functioning. The Metoprolol in Dilated Cardiomyopathy (MDC) trial was conducted as a large, multicenter trial to establish the effects of metoprolol on mortality and need for heart transplantation in patients with symptomatic idiopathic cardiomyopathy. It was found that metoprolol was well tolerated, improved symptoms and cardiac function, and prevented clinical deterioration in patients with symptomatic idiopathic dilated cardiomyopathy. Quality of life was evaluated as a secondary endpoint in 345 out of 383 randomized patients using a disease-specific questionnaire, the Quality of Life in Heart Failure Questionnaire, depicting physical activity, somatic symptoms, emotions, and life satisfaction. In a comparison of patients treated with metoprolol or placebo, patients treated with metoprolol noted a significantly more favorable response than those treated with placebo in terms of the overall treatment evaluation (p<0.05). Additionally, an analysis of the changes from baseline to 18 months, using 95% confidence intervals, revealed that patients treated with metoprolol showed a significant improvement from baseline to 18 months in life satisfaction, physical activity, and the total score, while patients treated with placebo did not change at all. The improvement in quality of life was supported by the correlations with improvement in traditional clinical parameters.     

Unsteady Fluid Dynamics of Several Mechanical Prosthetic Heart Valves Using a Two Component Laser Doppler Anemometer System

Abstract: Five typical mechanical heart valves (Starr-Edwards, Björk-Shiley convexo-concave (c-c), Björk-Shiley monostrut, Bicer-Val, and St. Jude Medical) were tested in the mitral position under the pulsatile flow condition. The test program included measurements of velocity and turbulent stresses at 5 downstream locations. The study was carried out using a sophisticated cardiac simulator in conjunction with a highly sensitive 2 component laser Doppler anemometer (LDA) system. The continuous monitoring of parametric time histories revealed useful details about the complex flow and helped to establish the locations and times of the peak parameter values. Based upon the nondimensional presentation of data, the following general conclusions can be made. First, all the 5 valve designs created elevated turbulent stresses during the accelerating and peak flow phases, presenting the possibility of thromboembolism and perhaps hemolysis. Second, the difference in valve configuration seemed to affect the flow characteristics; third, the bileaflet design of the St. Jude valve appeared to create a lower turbulence stress level.     

Subclinical pulmonary oedema and intermittent haemodialysis

It has been postulated that patients with chronic renal failure,even in the absence of cardiopulmonary symptoms, accumulateinterstitial pulmonary fluid, which is removed by haemodialysis.To test this hypothesis we used the indocyanine green (ICG)-heavywater double indicator dilution method to measure lung water,cardiac output, and central blood volume in relation to haemodialysis.Ten uraemic patients, without cardiopulmonary symptoms, wereinvestigated at the beginning and end, and 2 h after, a regulardialysis session. A group of 18 surgical patients about to undergoelective abdominal surgery served as controls. Despite normalgas exchange, central blood volume, and cardiac output at thestart of dialysis the mean (SD) lung water was significantlyhigher than in the control group [4.8 (0.9) compared with 3.6(0.7) ml/kg, P<0.001]. There was no correlation between weightgain between sessions of dialysis and the magnitude of lungwater at the start of dialysis. Lung water decreased (P <0.001)to the level of the control group in response to dialysis. Therewas no correlation between weight loss and reduction in lungwater induced by dialysis. In conclusion, we have verified thepresence of subclinical pulmonary oedema which was removed bydialysis in a group of patients with established renal failure.The variations in lung water cannot be explained by hydrostaticmechanisms alone.     

Nutritional aspects of Acute Renal Failure

The patient with acute renal failure is a very ill patient suffering from high urea levels causing poor appetite, nausea and vomiting. These patients are usually treated with a low sodium, low protein and, if the potassium in the blood is high, with a low potassium diet (1). This paper discusses whether or not this is the correct treatment. The symptoms of high urea levels in the blood together with increased needs for energy and protein makes it very hard to prevent the patient becoming malnourished. Often energy‐enriched drinks are necessary to achieve recommendations and it is prudent to let the patient eat and drink what they desire. By calculating the energy and protein needs and comparing these with the intake and the state of illness and by following the patient's body weight over time we can obtain information about the state of nourishment. When we alter the food that's offered we achieve better intake and reduce the risk of malnourishment.     

Effects of synchronization in the pacemaker during high-frequency atrial stimulation

I. M. Sechenov Medical Academy, Moscow. (Presented by Academician of the Academy of Medical Sciences of the USSR A. D. Ado.) Translated from Byulleten' Éksperimental'noi Biologii i Meditsiny, Vol. 111, No. 5, pp. 454–456, May, 1991.     

A Biomechanical Double Sac (Pericardium-Pebax) for Specially Shaped Artificial Ventricles: A Computerized Study to Evaluate Its Mechanical and Volumetric Properties

Abstract: For original ovoid shaped artificial ventricles. a biomechanical double sac consisting of a biological sac (porcine pericardium) as the blood contact interface and a synthetic sac (Pebax 3533) as the mechanical support to assume systolic-diastolic dynamic constraints was conceived. The volumetric and mechanical properties were assessed with a three-dimensional modeling of Pebax sacs and computerized simulations of their systolic distortions for both right and left ventricular configurations. The stresses and strains of these sacs were represented as quantitative mappings for a maximum end-systolic state and were below the respective threshold values above which the Pebax material is jeopardized for permanent structure impairment. After fatigue tests applied on Pebax strips under the alleged working conditions of Pebax sacs, the material structure was unchanged and maintained its intrinsic mechanical properties. The theoretical maximum stroke volumes were 74.4 cm³ and 62.4 cm for the left and right ventricular configurations, respectively. With these mechanical and volumetric features, the biomechanical double sac concept was considered valid and could be provided for a consequent specific total artificial heart.     

Recurrence risk for major congenital heart defects in Sweden: A registry study

During the period 1981–1986, 1605 infants presenting a major congenital heart defect (CHD) were identified in Sweden. Using the personal identification numbers of the mothers, 1507 of them could be linked to the Medical Birth Registry and two controls were selected for each infant. For this total of 4521 infants, 2686 postoccurrence sibs born during the period 1981–1989 were identified from the Medical Birth Registry. The tendency to have one or more sibs was higher among cases than among controls and was correlated to the life status of the proband. This tendency did not vary according to the type of CHD when controlling for life status. The prevalence at birth of CHD was almost four times higher among sibs of CHD infants than among sibs of normal infants. The tendency to have a sib with an extracardiac malformation did not differ between CHD probands and normal probands. The importance of only including births occurring after the proband when evaluating recurrence risks is stressed. © 1994 Wiley-Liss, Inc.     

开放手术观察腰椎间盘突出症溶核失败45例分析

目的 通过开放手术观察分析椎间盘髓核化学溶解术治疗腰椎间盘突出症失败原因。方法 收集溶核失败的腰椎间盘突出症45例行开放手术治疗。结果 术中见45例硬膜外脂肪完全消失，43例髓核未见溶解，2例髓核溶解呈糊状但未被吸收，21例伴有侧隐窝狭窄，15例突出物与神经根粘连，20例黄韧带增厚，2例椎管骨性狭窄，14例突出物钙化。结论 腰椎间盘突出症病变间隙合并有侧隐窝狭窄、神经根粘连、椎管狭窄、突出物钙化等，不是溶核治疗的适应证。